A vehicle using an internal combustion engine using gasoline or heavy oil as main fuel has a serious effect on generation of pollution such as air pollution, or the like.
Therefore, in order to reduce the generation of the pollution, an electric vehicle or a hybrid electric vehicle has been recently developed actively.
The electric vehicle is a vehicle operated using only electric energy output from a battery. Since the electric vehicle uses a battery in which a plurality of secondary batteries that may be charged and discharged are formed as a single pack as a main power source, it does not generate exhaust gas and has significantly small noise.
Meanwhile, the hybrid vehicle, which is an intermediate stage vehicle between a vehicle using an internal combustion engine and an electric vehicle, is a vehicle using two or more power sources, for example, an internal combustion engine and a battery engine.
In the vehicle using the electric energy as described above, since performance of a battery has a direct effect on performance of the vehicle, performance of each battery cell should be excellent. In addition, a battery managing system capable of efficiently managing charging and discharging and a lifespan of each battery cell by measuring voltage of each battery cell, voltage and current of the entire battery, and the like, has been urgently demanded.
Korean Patent Laid-Open Publication No. 2011-0006266 has disclosed a method for measuring internal resistance of a cell in a high voltage battery for a vehicle. The method for measuring internal resistance of a cell in a high voltage battery for a vehicle disclosed in Korean Patent Laid-Open Publication No. 2011-0006266 includes: measuring current and voltage of a battery; and receiving the measured current and voltage values and measuring battery resistance by a method of least squares.
The present invention relates to an apparatus and method for estimating internal resistance of a battery pack by observing a change in current used in the battery pack and using a current value satisfying a set current change condition and a voltage and temperature values according to the current value, as described above.
Since conditions specified in Korean Patent Laid-Open Publication No. 2011-0006266 are different in a standard and a feature from those of the present invention and correspond to conditions at a step following a step specified in the present invention, Korean Patent Laid-open Publication No. 2011-0006266 is not similar to the present invention.